You mentioned that you want to maintain the beauty of new wood, and while this is possible, it will require ongoing and somewhat vigorous maintenance. There’s no way around it. The best tinted, transparent finishes, for instance, last about two years in the sun; longer in the shade. After this you’ll need to strip, sand and reapply more finish. That disappointing, two month lifespan of the stain you applied a few years ago is common, but not inevitable. Many deck finishes perform poorly, though not all do.
If you want to restore the look of new wood to your deck, then sanding alone will work, though you’ll do better by pressure washing first, then sanding when the wood is completely dry. This two-step process is actually faster than sanding alone. Gentle pressure washing is a very fast way to clean old wood and remove a finish, but it often leaves fuzzy, frazzled surface fibers behind. This is especially true with cedar, since it’s so soft. I’d begin by applying a deck stripper if any original finish remains, then pressure wash the surface, keeping the nozzle 12″ to 16″ away from the wood. Any closer and you risk damage. Let the deck dry for a couple of sunny days, then sand with a random orbit sander spinning an 80-grit abrasive disk. This is a very quick operation that removes any loosened surface fibers caused by pressure washing. It’s much faster than sanding alone to remove and brighten the wood.